let say i want to do this

  var dasboard = {};

  $('.check').click(function(){ 
    $(this).toggleClass("active").siblings().slideToggle('slow', function() {
        dashboard['pages']['pagename'][$(this).closest('li').attr("id")]['show'] = $(this).is(":hidden") ? 'collapsed' : 'expanded';
    });
  }

i get an error saying 'dashboard.pages is undefined'

is there away to dynamically add 'pages' and the children that follow without having to do the work of checking to see if it is defined first then if its not doing

   dashboard['pages'] = {};

because sometimes they may already exist and I don't want to have to inspect the tree first i just want to build the branches as needed